JP5451311B2 - Electrophotographic capsule toner - Google Patents

Description

  The present invention relates to an electrophotographic capsule toner, a developer containing the toner, a fixing device for the toner, and an image forming apparatus using the toner.

In electrophotography, an electrostatic latent image is formed on a photosensitive drum using a photoconductive phenomenon, and the electrostatic latent image is developed with toner to form a toner image (visible image). This is an image forming method for transferring and fixing on a recording sheet.
Various fixing devices using heat, pressure, and light are used for fixing a toner image. For example, a fixing device using a heat roll is most commonly used.

  The fixing device using a heat roll has high thermal efficiency, but in addition to the loss time of about several tens of seconds in the initial heating (rise) of the device, the toner remaining on the heat roll easily contaminates the recording paper due to the offset. . Further, since the recording paper is nipped by a pair of heat rolls, wrinkles and tears are likely to occur when the recording paper is continuously fed.

  A fixing device using pressure is attracting attention due to advantages such as no warming up and no heat source. However, in this type of fixing device, it is difficult to firmly fix the toner image onto the recording paper, and pressure is applied through the recording paper between the pair of rolls, so that wrinkles and tears are likely to occur due to meandering. In addition, when a label-fed paper for label production, which has been used frequently recently, is used as a recording paper, the glue may protrude from the base.

  On the other hand, in the fixing device using light, the toner selectively absorbs light energy from flash light such as a xenon lamp and melts, so that the toner image can be fixed at high speed. Further, since fixing can be performed on the recording paper in a non-contact manner, there is no risk of wrinkling or tearing due to toner offset on the recording paper or meandering of the recording paper, and there is an advantage that no glue sticks out when using glued paper. .

  On the other hand, in flash fixing, since black toner absorbs light of all wavelengths, strong fixing light in the near-infrared region of 800 to 1000 nm of a xenon lamp can be absorbed and sufficient fixing characteristics can be obtained. Color toners such as toner, magenta toner, and yellow toner hardly absorb in the near infrared region, and it is difficult to obtain sufficient fixing characteristics.

For this countermeasure, Patent Document 1 proposes to add an infrared absorbent that absorbs light in the near infrared region to the color toner.
However, infrared absorbers having strong absorption in the near infrared region also have absorption in the visible region of 780 nm or less. Therefore, when an amount necessary for obtaining sufficient fixing properties is added to the color toner, The color reproducibility of the toner image is deteriorated due to light absorption.

  Therefore, in Patent Document 2, in order to reduce the amount of infrared absorber added to the toner, flash fixing and laser fixing are combined, laser light dedicated to each color toner is used for laser fixing, and the wavelength of the laser light is changed to each color toner. Has proposed a fixing method and apparatus in which the efficiency of supplying heat to the toner is increased by matching the maximum absorption wavelength of the toner.

Japanese Patent Laid-Open No. 11-38667 JP 2008-107576 A

However, even if the fixing method described in Patent Document 2 is used, the amount of the infrared absorber added cannot be effectively reduced, and there remains a problem that the color reproducibility of the toner image is still poor. .
Further, the fixing method described in Patent Document 2 requires two units of flash fixing and laser fixing as a fixing mechanism, which causes a problem that the apparatus configuration is complicated and the cost is increased.

  The present invention has been made in view of the above problems, and an object of the present invention is to form a toner image with good color reproducibility and to ensure sufficient fixability only by laser fixing, and the toner. To provide a toner fixing method and apparatus.

  As a result of diligent efforts to achieve the above object, the present inventors have found that the intended toner can be obtained by optimizing the light absorption efficiency of the toner itself.

  Accordingly, the present invention comprises a core particle comprising at least a binder resin and colorant fine particles, and a coating layer comprising at least a binder resin and colorant fine particles and covering the core particles, and coloring in the core particles The volume average particle diameter a of the agent fine particles and the volume average particle diameter b of the colorant fine particles in the coating layer have the following relationship: 2.0 ≦ a / b ≦ 5.0 and 0.5 μm ≦ a ≦ 0.9 μm And a capsule toner for electrophotography having a core-shell structure, wherein only a laser beam is irradiated for fixing.

  The present invention also melts the toner by irradiating an unfixed toner image formed with the toner on the recording medium with a laser beam having a wavelength within the absorption wavelength range of the colorant fine particles contained in the toner. Then, the toner image is fixed on the recording medium by solidifying again, and a toner fixing method is provided.

The present invention further uses at least one one-component developer comprising the toner and an external additive or two-component developer comprising the toner and a carrier, and a toner in the developer. an unfixed toner image formed by a fixing device for fixing on a recording medium, prior provided with means for heating and melting Quito toner, coloring said means are included in the respective front Quito toner in the toner A fixing device comprising at least one laser light source for irradiating laser light having a wavelength within the absorption wavelength range of the agent fine particles, and including only the laser light source as a light source for irradiating light to the toner is provided. To do.

According to the present invention, it is possible to effectively reduce the amount of the infrared absorbent added to the color toner. As a result, it is possible to provide a toner that can form a toner image with good color reproducibility and can secure sufficient fixability only by laser fixing.
Further, according to the present invention, there is provided a toner image fixing method and apparatus capable of achieving sufficient fixing performance at low cost without deteriorating color reproducibility.

FIG. 3 is a schematic diagram illustrating one embodiment of a capsule toner of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a fixing device of the present invention. 1 is a schematic cross-sectional view showing one embodiment of an image forming apparatus of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a developing device used in an image forming apparatus of the present invention.

  An electrophotographic capsule toner having a core-shell structure according to the present invention includes a core particle comprising at least a binder resin and colorant fine particles, and a coat layer comprising at least the binder resin and colorant fine particles and covering the core particles. The volume average particle diameter a of the colorant fine particles in the core particles and the volume average particle diameter b of the colorant fine particles in the coat layer have the following relationship: 2.0 ≦ a / b ≦ 5.0 And 0.5 μm ≦ a ≦ 0.9 μm, and only fixing is performed with laser light.

  In the conventional toner, the particle diameter of the pigment (colored resin fine particles) is the same throughout the toner (toner base particles), and it is not considered to diffuse (diffuse reflection) incident light to the peripheral toner. For this reason, in the toner particle layer forming the toner image, the toner particles in the region not directly irradiated with the laser beam are not irradiated with a sufficient amount of light, and the toner is sufficiently heated only by the laser beam irradiation. It cannot melt. Therefore, the toner particle layer cannot be uniformly fixed on the recording medium.

On the other hand, in the toner of the present invention, the particle diameter of the pigment (colorant fine particles) is different in the core particle and in the coat layer and is larger in the core particle.
For this reason, most of the light incident on the coat layer is transmitted through the coat layer and incident on the core particles or incident on the lower toner, while most of the light incident on the core particles is the colorant fine particles. In this case, a part is absorbed (converted into heat energy and used for melting the toner), and the rest is diffusely reflected and irradiated to surrounding toner.
That is, the balance between the amount of absorption inside the toner particles directly irradiated with laser light and the light irradiation to the surrounding toner particles (not directly irradiated with laser light) is good.

  Further, the light transmittance of the entire toner particles can be maintained high. As a result, the laser beam irradiation efficiency of the entire toner particle layer forming the toner image is improved, and the toner particle layer can be sufficiently heated and melted only by the laser beam. Can be sufficiently secured. As a result, it is not necessary to further add an infrared absorber to the toner in order to obtain toner fixing characteristics, and an image can be obtained in which the color reproducibility caused by the infrared absorber does not deteriorate.

When the ratio a / b is smaller than 2.0, the transmittance of the irregular light from the core particles is lowered and the toner particle layer is not sufficiently fixed. On the other hand, when the ratio a / b is larger than 5.0, the core particles and the shell layer are not fixed. Thus, the difference in absorption efficiency increases, and the melt state of the core particles and the shell layer differ greatly, and uniform fixing cannot be performed.
Further, when a is smaller than 0.5 μm, the value that b can take (that is, the volume average particle diameter of the colorant in the shell layer) becomes too small. Therefore, the dispersion state of the colorant in the shell layer As a result, the light transmittance is lowered, and as a result, the irradiation efficiency of the laser light is lowered, and the fixing of the toner particle layer becomes insufficient. Further, due to the deterioration of the dispersion state, the molten state in the shell layer is greatly different, and uniform fixing cannot be performed. On the other hand, when the thickness is larger than 0.9 μm, the light transmittance of the core particles is lowered, and the laser light cannot be emitted outside the toner particles, so that the toner particle layer is not sufficiently fixed.

Hereinafter, the configuration of the toner of the present invention and the production method thereof will be described.
FIG. 1 is a schematic view showing a configuration of one embodiment of a capsule toner having a core-shell structure of the present invention. The capsule toner 1 has a two-layer structure (core-shell structure) including a shell layer (coating layer) 3 on the surface of the core particle 2. The core particle 2 is formed by dispersing the colorant fine particles C1 in the binder resin, and the shell layer 3 is formed by dispersing the colorant fine particles C2 in the binder resin.
The toner of the present invention is preferably a color toner other than cyan toner, magenta toner, yellow toner, or black toner. Since the black toner has good light absorption efficiency, it is not necessary to use the configuration of the present invention.
When the toner of the present invention is a color toner, the effect that an image in which the color reproducibility caused by the infrared absorbent does not deteriorate can be obtained more remarkably.

<Core particles>
The core particle is composed of at least a binder resin and colored resin fine particles.
In the toner of the present invention, the volume average particle diameter a of the colorant fine particles contained in the core particles is in the range of 0.5 μm ≦ a ≦ 0.9 μm, and the volume of the colorant fine particles contained in the shell layer described later. It is necessary that the ratio a / b with the average particle diameter b satisfies 2.0 ≦ a / b ≦ 5.0.

The binder resin contained in the core particles (hereinafter also referred to as “first binder resin”) is not particularly limited, and any binder resin that can be used for toner can be used. . Examples of the binder resin include polyester resins, styrene resins such as polystyrene and styrene-acrylate copolymer resins, acrylic resins such as polymethyl methacrylate (hereinafter referred to as “PMMA”), and polyolefins such as polyethylene. Resin, polyurethane, epoxy resin, silicon resin and the like.
As the first binder resin, one kind of binder resin may be used alone, or two or more kinds of binder resins may be used in combination.

As the colorant fine particles contained in the core particles, any of dyes and pigments known to be used as toner colorants can be used. Among these, it is preferable to use a pigment. Since the pigment is superior in light resistance and color developability compared to the dye, a toner having excellent light resistance and color developability can be obtained by using the pigment.
Examples of the colorant include a yellow toner colorant, a magenta toner colorant, a cyan toner colorant, and a black toner colorant.

  Examples of the colorant for yellow toner include CI pigment yellow 1, CI pigment yellow 5, CI pigment yellow 12, CI pigment yellow 15, and C classified by color index. Organic pigments such as CI Pigment Yellow 17, CI Pigment Yellow 74, CI Pigment Yellow 93, CI Pigment Yellow 180, CI Pigment Yellow 185, etc .: yellow iron oxide, loess, etc. Inorganic pigments: Nitro dyes such as CI Acid Yellow 1 CI Solvent Yellow 2, CI Solvent Yellow 6, CI Solvent Yellow 14, CI Solvent Yellow 15, Examples thereof include oil-soluble dyes such as CI Solvent Yellow 19 and CI Solvent Yellow 21.

  Examples of the colorant for magenta toner include CI Pigment Red 49, CI Pigment Red 57, CI Pigment Red 81, CI Pigment Red 122, and C.I. And CI Solvent Red 19, CI Solvent Red 49, CI Solvent Red 52, CI Basic Red 10, CI Disperse Red 15, and the like.

  Examples of the colorant for cyan toner include CI pigment blue 15, CI pigment blue 16, CI solvent blue 55, CI solvent blue 70, and C.I. And CI Direct Blue 25, CI Direct Blue 86, and the like.

Examples of the colorant for black toner include carbon black such as channel black, roller black, disk black, gas furnace black, oil furnace black, thermal black, and acetylene black.
In addition to the above colorants, red pigments, green pigments and the like can be used. These colorants may be used alone or in combination of two or more different colors. Also, a plurality of colorants of the same color can be used in combination.

  The content of the colorant in the core particles is not particularly limited. For example, the colorant may be in the range of 4 to 20 parts by weight with respect to 100 parts by weight of the binder resin. preferable. Thereby, the filler effect by addition of a coloring agent can be suppressed, and a toner having high coloring power can be obtained. On the other hand, if the content of the colorant in the toner exceeds 20 parts by weight, the fixability of the toner may be lowered due to the filler effect of the colorant.

  The core particles may further contain various substances used as an additive of the toner, for example, a charge control agent, if necessary.

Charge Control Agent A charge control agent for toner is added to give a preferable chargeability to the toner. The charge control agent used in the present invention is not particularly limited, and conventionally known charge control agents for positive charge control or negative charge control can be used.
Examples of charge control agents for positive charge control include nigrosine dyes, basic dyes, quaternary ammonium salts, quaternary phosphonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, nigrosine dyes and derivatives thereof, triphenylmethane Examples thereof include derivatives, guanidine salts, and amidine salts.

Examples of charge control agents for controlling negative charges include oil-soluble dyes such as oil black and spiron black: metal-containing azo compounds, azo complex dyes, naphthenic acid metal salts, metal complexes of salicylic acid and its derivatives, and metals. Examples thereof include salts (metals such as chromium, zinc and zirconium), boron compounds, fatty acid soaps, long-chain alkyl carboxylates, and resin acid soaps.
These charge control agents may be used alone or in combination of two or more charge control agents.

The charge control agent is preferably used in the range of 0.5 to 5 parts by weight, and in the range of 0.5 to 3 parts by weight, based on 100 parts by weight of the binder resin. More preferred.
When the charge control agent is contained in an amount of more than 5 parts by weight based on 100 parts by weight of the binder resin, the carrier is contaminated when used as a two-component developer, and toner scattering occurs. Further, when the charge control agent is less than 0.5 part by weight with respect to 100 parts by weight of the binder resin, sufficient charging characteristics cannot be imparted to the toner.

  The volume average particle diameter of the core particles is not particularly limited, but may be, for example, 3 to 10 μm, and preferably 5 to 8 μm.

<Shell layer>
The shell layer is composed of at least a binder resin and colorant fine particles.
In the toner of the present invention, the volume average particle diameter b of the colorant fine particles contained in the shell layer is such that the ratio a / b of the volume average particle diameter a of the colorant fine particles contained in the core particles is 2.0 ≦ a / It is necessary to satisfy b ≦ 5.0. The volume average particle diameter b is not particularly limited as long as the ratio a / b is within the above range, but is preferably in the range of 0.1 μm ≦ b ≦ 0.4 μm.

  The thickness of the shell layer is preferably 0.3 μm or more, for example, 0.3 to 2 μm. If the thickness is less than 0.3 μm, it is difficult to form a uniform shell layer on the core particles, and in addition, it becomes difficult to control light transmission and (random) reflection.

  The binder resin contained in the shell layer (hereinafter also referred to as “second binder resin”) is not particularly limited, and any binder resin that can be used for toner can be used. For example, the binder resin particle mentioned regarding the core particle can be mentioned. As the second binder resin, one kind of binder resin may be used alone, or two or more kinds of binder resins may be used in combination. The second binder resin may be the same as or different from the first binder resin contained in the core particles.

As the colorant fine particles contained in the shell layer, any of dyes and pigments known to be used as toner colorants can be used, and examples thereof include the colorants mentioned for the core particles.
Also in the shell layer, one type of colorant may be used alone, or two or more types having different colors may be used in combination. Also, a plurality of colorants of the same color can be used in combination.
The colorant fine particles contained in the shell layer are generally the same as the colorant fine particles contained in the core particles, but may be different as long as the volume average particle diameter satisfies the predetermined relationship.

  The content of the colorant in the shell layer is not particularly limited. For example, the colorant may be in the range of 4 to 20 parts by weight with respect to 100 parts by weight of the binder resin. preferable. Thereby, the filler effect by addition of a coloring agent can be suppressed, and a toner having high coloring power can be obtained. On the other hand, if the content of the colorant in the toner exceeds 20 parts by weight, the fixability of the toner may be lowered due to the filler effect of the colorant.

The shell layer may further contain various substances used as an additive for the toner, for example, a release agent, a charge control agent, and the like, if necessary.
The release agent and charge control agent in the shell layer are as described for the core particles.
The additive in the shell layer may be the same as or different from the additive in the core particle.
It is preferable that the capsule toner of the present invention does not substantially contain an infrared absorber in both the core particles and the shell layer. Here, “substantially free” of the infrared absorber means that the infrared absorber is not contained in an amount that affects the color reproducibility of the toner image. Such an amount is, for example, 0.1 parts by weight or less with respect to 100 parts by weight of the binder resin.

<Method for producing capsule toner>
The method for producing the capsule toner of the present invention is not particularly limited as long as the core-shell structure is formed, and can be produced by a known production method, for example, an aggregation method.
Below, the manufacturing method of a core particle and the formation method of a shell layer (core-shell structure) are demonstrated in detail.

Production method of core particles The core particles can be produced by a conventionally known toner production method, for example, a melt-kneading pulverization method. The melt-kneading pulverization method was obtained by a dry mixing of core particle materials including a binder resin and colorant fine particles, and a release agent, a charge control agent and other additives as necessary, and a mixing step. A melt-kneading step of melt-kneading the mixture, a cooling step of cooling and solidifying the melt-kneaded product obtained in the melt-kneading step, and a pulverizing step of mechanically pulverizing the solidified product obtained in the cooling step.

  The colorant is preferably used as a master batch. The master batch of the colorant can be produced, for example, by kneading the binder resin melt and the colorant. As the binder resin used in the master batch, a resin of the same type as the toner binder resin or a resin having good compatibility with the toner binder resin is used. The use ratio of the binder resin and the colorant in the masterbatch is not particularly limited, but the colorant is used in the range of 30 parts by weight to 100 parts by weight with respect to 100 parts by weight of the binder resin. It is preferred that The particle size of the master batch is not particularly limited, but it is preferable that the master batch is granulated to have a particle size of about 2 to 3 mm, for example.

  In the mixing step, the mixer used for dry mixing is not particularly limited, and a known mixer can be used. For example, Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), Super mixer (trade name, manufactured by Kawata Co., Ltd.), Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.), etc. , Hosokawa Micron Corporation), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo System (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), and the like.

In the melt-kneading step, the mixture obtained in the mixing step is stirred and kneaded while being heated to a temperature equal to or higher than the melting temperature of the binder resin. Here, “the temperature equal to or higher than the melting temperature of the binder resin” is usually about 80 to 200 ° C., preferably about 100 to 150 ° C.
The kneader used in the melt-kneading step is not particularly limited, and for example, a general kneader such as a twin screw extruder, a triple roll, a lab blast mill can be used. More specifically, for example, a uniaxial or biaxial extruder such as TEM-100B (trade name, manufactured by Toshiba Machine Co., Ltd.), PCM-65 / 87 (trade name, manufactured by Ikegai Co., Ltd.), Needex ( An open roll type product such as a trade name, manufactured by Mitsui Mining Co., Ltd.) can be used.

  In the pulverization step, a cutter mill, a feather mill, a jet mill or the like is used for pulverization of the solidified product obtained by cooling the melt-kneaded product. These pulverizers may be used alone or in combination of two or more. For example, the solidified product is roughly pulverized with a cutter mill and then pulverized with a jet mill to obtain core particles having a desired volume average particle diameter.

  The core particles are also obtained by roughly pulverizing the solidified product of the melt-kneaded product in the pulverization step, and then turning the obtained coarsely pulverized product into an aqueous slurry, treating the aqueous slurry with a high-pressure homogenizer, and pulverizing the resulting fine particles into an aqueous solution. It can also be produced by heating in a medium to cause aggregation and melting.

  Specifically, coarse powder having a particle diameter of about 100 μm to 3 mm is obtained by coarse pulverization. The coarse pulverization of the solidified product of the melt-kneaded product is performed using, for example, a jet mill or a hand mill. The obtained coarse powder is dispersed in water to prepare an aqueous slurry. In preparing the aqueous slurry, it is preferable to dissolve an appropriate amount of a dispersant such as sodium dodecylbenzenesulfonate in water from the viewpoint of uniformly dispersing the coarse powder in water.

Next, by treating the obtained aqueous slurry with a high-pressure homogenizer, the coarse powder in the aqueous slurry is atomized to obtain an aqueous slurry containing fine particles having a volume average particle diameter of about 0.4 to 1.0 μm. The aqueous slurry containing the fine particles is heated, the fine particles are aggregated, and the fine particles are melted and bonded to obtain core particles having a desired volume average particle diameter and average circularity.
For example, core particles having a desired volume average particle diameter and average circularity can be obtained by appropriately selecting the heating temperature and heating time of the fine aqueous slurry. The heating temperature is appropriately selected from a temperature range above the softening point of the binder resin and below the thermal decomposition temperature of the binder resin. When the heating time is the same, normally, the higher the heating temperature, the larger the volume average particle diameter of the resulting core particles.

  As the high-pressure homogenizer, for example, as a commercial product of the high-pressure homogenizer, for example, microfluidizer (trade name, manufactured by Microfluidics), nanomizer (trade name, manufactured by Nanomizer), optimizer (trade name, High pressure homogenizer (trade name, manufactured by Rannie), high pressure homogenizer (trade name, manufactured by Sanmaru Machinery Co., Ltd.), high pressure homogenizer (trade name, manufactured by Sugino Machine Co., Ltd.) Izumi Food Machinery Co., Ltd.), NANO3000 (trade name, manufactured by Migrain Co., Ltd.) and the like.

  The core particles may be further spheroidized. Examples of the spheroidizing means include an impact spheronizing device and a hot air spheronizing device. As the impact spheroidizing device, a commercially available device can be used, for example, using a faculty (trade name, manufactured by Hosokawa Micron Corporation), a hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), etc. Can do. As the hot-air spheronization apparatus, a commercially available apparatus can be used, and for example, a surface reformer meteoreinbo (trade name, manufactured by Nippon Pneumatic Industry Co., Ltd.) can be used.

Shell layer formation method (Method of forming a two-layer structure by encapsulation)
The capsule toner particles of the present invention are prepared by adding a dispersion of shell particles, which will be described later, to the core particle dispersion to agglomerate and fuse the shell particles on the surface of the core particles and coat the surface of the core particles with the shell particles. Form.

The shell particles can be prepared by any known method, but can be obtained by emulsifying and dispersing with a homogenizer or the like by the method described for the core particles.
The shell particles have a volume average particle diameter of, for example, 0.1 to 1.0 μm.

  The dispersion of core particles and shell particles can be prepared by a conventionally known method. The dispersion in which the particles are dispersed is not particularly limited as long as the particles are dispersed in a dispersion medium such as water, but the dispersion is adjusted by emulsion polymerization or soap-free emulsion polymerization. It is possible to use a liquid.

For example, the obtained core particles and shell particles and a liquid dispersion medium are mixed in, for example, a mixer or a stirrer, and the core particles and the shell particles are dispersed in the liquid dispersion medium, thereby containing the core particles and the shell particles. A slurry is prepared.
The liquid dispersion medium may be any liquid that can be uniformly dispersed without dissolving the core particles and the shell particles. Water is preferable in terms of ease of handling.

The ratio of the core particles and the shell particles contained in the slurry is, for example, 22 to 45% by weight, preferably 22 to 43% by weight, more preferably 25 to 40% by weight, based on the total weight of the liquid dispersion medium and the particles. .
The weight ratio C / S between the core particles (C) and the shell particles (S) in the slurry is, for example, 80/20 to 96/4.

The liquid dispersion medium preferably contains a dispersant. Any dispersant can be used as long as it dissolves in a liquid dispersion medium (particularly water-soluble) and facilitates the dispersion of core particles and shell particles. Among these, a polymer dispersant is preferable.
A dispersing agent may be used individually by 1 type, and may use 2 or more types together.
The amount of the dispersant added to the liquid dispersion medium is, for example, 5 to 10% by weight.

The slurry containing the core particles and the shell particles is stirred while heating to adhere the shell particles to the surface of the core particles.
Stirring can be performed by a known stirring means, for example, a rotor / screen type high-speed emulsification improver. The stirring speed is, for example, 12 to 25 m / second, preferably 14 to 22 m / second, more preferably 16 to 20 m / second, as the peripheral speed of the tip (radially outer side) of the stirring blade (rotor).

The heating temperature is preferably higher than the glass transition temperature of the first binder resin contained in the core particles, for example, 5 to 10 ° C higher.
After fixing the shell particles to the surface of the core particles as described above, the particles are taken out of the slurry, for example, by filtration, washed with water as necessary, and dried to dry the core and the shell covering the surface of the core A capsule toner having a core-shell structure consisting of

<Developer>
The developer of the present invention is a one-component developer or a two-component developer comprising the capsule toner according to the present invention.
When the capsule toner according to the present invention is used as a one-component developer, only the toner is used without using a carrier.
When used as a one-component developer, a blade and a fur brush are used, frictionally charged by a developing sleeve, and the toner is transported by adhering the toner onto the sleeve to form an image.

  When the capsule toner according to the present invention is used as a two-component developer, the toner is used together with a carrier. That is, the two-component developer according to the present invention includes the toner and the carrier having a high light absorption rate. Therefore, it is a two-component developer capable of ensuring sufficient fixability for a long period of time and obtaining an image without deterioration of color reproducibility due to the addition of an infrared absorber.

  As the carrier, those commonly used in this field can be used. For example, a resin-coated carrier made of iron, copper, zinc, nickel, cobalt, manganese, chromium, etc., alone or composite ferrite and carrier core particles coated with a coating material, or resin dispersion in which magnetic particles are dispersed in the resin Examples include mold carriers.

  The coating material is not particularly limited, and a known material can be used. For example, polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal compound of ditertiary butylsalicylic acid, styrenic resin, acrylic resin, polyacid, polyvinyllar, nigrosine, aminoacrylate resin, Examples include basic dyes, basic dye lakes, silica fine powders, and alumina fine powders. The resin used for the resin-dispersed carrier is not particularly limited, and examples thereof include styrene acrylic resin, polyester resin, fluorine resin, and phenol resin. Any of these is preferably selected according to the toner component, and one kind may be used alone, or two or more kinds may be used in combination.

The shape of the carrier is preferably a spherical shape or a flat shape. Further, the particle diameter of the carrier is not particularly limited, but it is preferably in the range of 10 to 100 μm, and more preferably in the range of 20 to 50 μm, considering high image quality. Furthermore, the resistivity of the carrier is preferably 10 ⁸ Ω · cm or more, and more preferably 10 ¹² Ω · cm or more. The “carrier resistivity” refers to a carrier having a cross-sectional area of 0.50 cm ² and a tapped electrode placed on the bottom, and a load of 1 kg / cm ² is applied to the carrier particles packed in the container. It is a value obtained by reading the current value when a voltage that generates an electric field of 1000 V / cm ² is applied between the load and the bottom electrode. When the resistivity is low, when a bias voltage is applied to the developing sleeve, charges are injected into the carrier, and carrier particles easily adhere to the photoreceptor. Further, breakdown of the bias voltage is likely to occur.

  The magnetization strength (maximum magnetization) of the carrier is preferably in the range of 10 to 60 emu / g, and more preferably in the range of 15 to 40 emu / g. The “magnetization strength” depends on the magnetic flux density of the developing roller. However, under the general magnetic flux density conditions of the developing roller, the magnetic binding force does not work if the magnetization strength of the carrier is less than 10 emu / g. May cause carrier scattering. On the other hand, if the “magnetization strength” exceeds 60 emu / g, the rising of the carrier becomes too high, and it becomes difficult to maintain the non-contact state with the image carrier by non-contact development. Further, in the contact development, there is a risk that a sweep is likely to appear in the toner image.

The use ratio of the toner and the carrier in the two-component developer is not particularly limited, and can be appropriately selected according to the types of the toner and the carrier. For example, when a resin-coated carrier (density 5 to 8 g / cm ² ) is used, the toner is used so that the developer contains 2 to 30% by weight, preferably 2 to 20% by weight of the total amount of the developer. That's fine. In the two-component developer, the coverage of the carrier with toner is preferably 40 to 80%.

  In the developer of the present invention, the capsule toner according to the present invention includes powder flowability improvement, triboelectric chargeability improvement, heat resistance improvement, long-term storage improvement, cleaning property improvement, and photoreceptor surface wear property control, etc. You may mix the external additive which bears a function. The external additive is not particularly limited, and those commonly used in this field can be used. Examples thereof include inorganic fine powders such as silica fine powder, titanium oxide fine powder and alumina fine powder. These inorganic fine powders are used for silicone varnish, various modified silicone varnishes, silicone oils, various modified silicone oils, silane coupling agents, and silane cups having functional groups for the purpose of hydrophobicizing the toner and controlling the chargeability of the toner. It is preferably treated with a treating agent such as a ring agent and other organosilicon compounds. The said external additive may be used individually by 1 type, and may use 2 or more types together.

The external additive preferably has a number average particle diameter of primary particles of 10 nm to 500 nm. By using an external additive having a particle size within the above range, the effect of improving the fluidity of the toner can be more easily exhibited.
In consideration of the charge amount necessary for the toner, the influence on the abrasion of the photoreceptor due to the addition of the external additive, and the environmental characteristics of the toner, the additive amount of the external additive is 1 with respect to 100 parts by weight of the toner particles. It is preferably 10 to 10 parts by weight, and more preferably 5 parts by weight or less.

<Fixing method and apparatus>
In the fixing method of the present invention, an unfixed toner image formed with a toner according to the present invention on a recording medium is irradiated with laser light having a wavelength within the absorption wavelength range of the colorant fine particles contained in the toner. The toner image is fixed on the recording medium by melting the toner and then solidifying it again.
The fixing method of the present invention can be implemented by, for example, the fixing device of the present invention described below.

The fixing device of the present invention is a fixing device for fixing an unfixed toner image formed of at least one toner according to the present invention on a recording medium, and comprises a means for heating and melting the at least one toner, The means includes at least one laser light source for irradiating each of the at least one toner with laser light having a wavelength within the absorption wavelength range of the colorant fine particles contained in each toner, and irradiating the toner with light. The light source to be used includes only the laser light source.
The fixing method and the fixing device according to the present invention perform fixing only with laser light using a toner that does not contain an infrared absorber, so that an image having no deterioration in color reproducibility due to the addition of the infrared absorber can be obtained. In addition, the cost is low.

Hereinafter, the electrophotographic fixing device of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a schematic diagram showing a configuration of one embodiment of the fixing device of the present invention. The illustrated laser fixing device 80 includes a laser light source 81 that generates laser light, and a rotating polygon mirror 82 that scans and exposes the endless belt 61 by reflecting the laser light emitted from the laser light source 81. .

The laser light source 81 is configured so that four laser beams having different wavelengths as oscillation wavelengths can be output separately. The rotary polygon mirror 82 is formed of, for example, a regular hexahedron, and rotates at a constant speed in the direction of the arrow in FIG.
The drive roller 62 is provided so that it can be rotated around its axis by a drive unit (not shown), and the endless belt 61 is rotationally driven in the direction of the arrow by the rotational drive. The driven roller 63 is provided so as to be able to rotate following the rotational driving of the driving roller 62, and applies a constant tension to the endless belt 61 so that the endless belt 61 does not loosen.

  A collimator lens, a cylinder lens, or the like can be provided in the optical path between the laser light source 81 and the rotary polygon mirror 82. Further, an fθ lens, a folding mirror, a reflection mirror, or the like can be provided between the rotary polygon mirror 82 and the endless belt 61.

  The laser fixing device 80 irradiates the toner held on the paper P with different light to fix the toner on the paper in a non-contact manner. The laser fixing device 80 locally irradiates the toner forming portion on the paper P with light.

The laser light source 81 can be composed of, for example, a Y fixing laser 81Y, an M fixing laser 81M, a C fixing laser 81C, and a K fixing laser 81K according to the toner to be fixed.
The Y fixing laser 81Y emits light at a wavelength corresponding to the absorption peak in the visible region of the yellow toner (that is, the absorption peak wavelength of the colorant contained in the yellow toner; for example, 430 nm).

The M fixing laser 81M emits light at a wavelength corresponding to the absorption peak in the visible region of the magenta toner (that is, the absorption peak wavelength of the colorant contained in the magenta toner; for example, 565 nm).
The C fixing laser 81C emits light at a wavelength corresponding to the absorption peak in the visible region of the cyan toner (that is, the absorption peak wavelength of the colorant contained in the cyan toner; for example, 620 nm).
The wavelength of the K fixing laser 81K is the absorption wavelength of the black toner. The emission wavelength of the K fixing laser 81K corresponding to the black toner absorption peak is not particularly limited and can be set as appropriate.

The intensity of the laser is preferably 1.5 W / cm ² or more 630 W / cm ² or less. When the intensity of the laser is weaker than 1.5 W / cm ² , the toner is not sufficiently melted by the laser irradiation, so that the fixing rate is lowered. On the other hand, when the fixing exposure energy is higher than 630 W / cm ² , the fixing rate is lowered because the toner and paper P are burnt by laser irradiation.

  While the paper P passes, the laser beam from the Y fixing laser 81Y is scanned by the rotary polygon mirror 82 and is applied to the toner held on the paper P. Then, since the emission wavelength of the Y fixing laser 81Y corresponds to the absorption wavelength of the yellow toner, the laser light emitted from the Y fixing laser 81Y is selectively absorbed by the yellow toner on the paper P, and the light is absorbed. The heated yellow toner melts.

  Subsequently, the laser beam from the M fixing laser 81M is scanned by the rotary polygon mirror 82 and is applied to the toner held on the paper P. Then, since the emission wavelength of the M fixing laser 81M corresponds to the absorption wavelength of the magenta toner, the laser light emitted from the M fixing laser 81M is selectively absorbed by the magenta toner on the paper P, and the light is absorbed. The heated magenta toner melts.

  Subsequently, the laser beam from the C fixing laser 81 </ b> C is scanned by the rotary polygon mirror 82 and is applied to the toner held on the paper P. Then, since the emission wavelength of the C fixing laser 81C corresponds to the absorption wavelength of the cyan toner, the laser light emitted from the C fixing laser 81C is selectively absorbed by the cyan toner on the paper P, and is absorbed by the light. The generated cyan toner melts.

Subsequently, the laser beam from the K fixing laser 81K is scanned by the rotary polygon mirror 82 and is applied to the toner held on the paper P. Then, since the emission wavelength of the K fixing laser 81K corresponds to the absorption wavelength of the black toner, the laser light emitted from the K fixing laser 81K is selectively absorbed by the black toner on the paper P, and the light is absorbed. The heated black toner melts.
The melted toner is solidified by natural cooling.

  As described above, the toner on the paper P is irradiated with the laser beam corresponding to the maximum absorption wavelength of each color toner. As a result, even if each color toner forming the toner image does not contain an infrared absorber, the toner image Is fixed on the paper P efficiently and / or uniformly, and an image having good fixability and color reproducibility is formed.

<Image forming apparatus>
Next, the electrophotographic image forming apparatus of the present invention will be described.
As long as the image forming apparatus of the present invention uses the developer according to the present invention described above as a developer and includes the fixing device according to the fixing method according to the present invention (for example, the fixing device according to the present invention described above), Other configurations are not limited to specific ones, and any known configuration of an electrophotographic image forming apparatus using an electrophotographic developer can be employed.

For example, the image forming apparatus of the present invention includes an image carrier (photosensitive drum) on which an electrostatic latent image is formed, a charging device that charges the surface of the image carrier, and an electrostatic latent image on the surface of the image carrier. An exposure apparatus for forming the toner, a developing apparatus for containing the developer according to the present invention and supplying toner to the electrostatic latent image on the surface of the image carrier to form a toner image, and a toner image on the surface of the image carrier The image forming apparatus may include a transfer device that transfers the toner image onto the recording medium, a cleaning device that cleans the surface of the image carrier, and a fixing device that fixes the toner image onto the recording medium using the fixing method according to the present invention described above.
The image forming apparatus of the present invention can be, for example, an electrophotographic copying machine, a printer, a facsimile machine, or a complex machine of these.

The image forming apparatus of the present invention will be specifically described below with reference to the drawings.
FIG. 3 is a cross-sectional view showing the configuration of one embodiment of the image forming apparatus of the present invention. The illustrated image forming apparatus 100 is a multifunction device having both a copying function, a printer function, and a facsimile function, and forms a full-color or monochrome image on a recording medium in accordance with transmitted image information. That is, the image forming apparatus 100 has three types of printing modes, ie, a copier mode (copying mode), a printer mode, and a FAX mode. Operation input from an operation unit (not shown), personal computer, portable terminal device, information A print mode is selected by a control unit (not shown) in response to reception of a print job from an external device using a recording storage medium or a memory device.

  The image forming apparatus 100 includes a toner image forming unit 7, a transfer unit 8, a fixing device 4, a recording medium supply unit 5, and a discharge unit 6. Each member constituting the toner image forming unit 7 and some members included in the transfer unit 8 are black (b), cyan (c), magenta (m), and yellow (y) colors included in the color image information. In order to correspond to the image information, four each are provided. Hereinafter, in the present specification, each member provided by four according to each color is distinguished by adding an alphabet representing each color to the end of the reference symbol, and when collectively referred to, only the reference symbol is used.

(Toner image forming part)
The toner image forming unit 7 includes a photosensitive drum 11, a charging unit 12, an exposure unit 13, a developing device 14, and a cleaning unit 15.
The charging unit 12, the developing device 14, and the cleaning unit 15 are arranged in this order around the rotation direction of the photosensitive drum 11. The charging unit 12 is disposed below the developing device 14 and the cleaning unit 15 in the vertical direction.

Photosensitive drum The photosensitive drum 11 is supported by a drive unit (not shown) so as to be rotatable around an axis, and includes a conductive substrate (not shown) and a photosensitive layer formed on the surface of the conductive substrate.

"Conductive substrate"
The conductive substrate can take various shapes, and examples thereof include a cylindrical shape, a columnar shape, and a thin film sheet shape. Among these, a cylindrical shape is preferable. The conductive substrate is formed of a conductive material.
As the conductive material, those commonly used in this field can be used. For example, metals such as aluminum, copper, brass, zinc, nickel, stainless steel, chromium, molybdenum, vanadium, indium, titanium, gold, and platinum, these A conductive layer made of one or more of aluminum, aluminum alloy, tin oxide, gold, indium oxide, etc. is formed on a film-like substrate such as two or more alloys, synthetic resin film, metal film, paper, etc. Examples thereof include a conductive film, a resin composition containing conductive particles and / or a conductive polymer. In addition, as a film-form base | substrate used for an electroconductive film, a synthetic resin film is preferable and a polyester film is especially preferable. Moreover, as a formation method of the electroconductive layer in an electroconductive film, vapor deposition, application | coating, etc. are preferable.

"Photosensitive layer"
The photosensitive layer is formed, for example, by laminating a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. In that case, it is preferable to provide an undercoat layer between the conductive substrate and the charge generation layer or the charge transport layer. By providing an undercoat layer, the scratches and irregularities present on the surface of the conductive substrate are coated to smooth the surface of the photosensitive layer, preventing deterioration of the chargeability of the photosensitive layer during repeated use, at low temperatures and / or Or the advantage that the charging characteristic of the photosensitive layer in a low-humidity environment is improved is obtained. Further, a laminated photoreceptor having a three-layer structure having a high durability and having a photoreceptor surface protective layer as the uppermost layer may be used.

  The charge generation layer is mainly composed of a charge generation material that generates a charge when irradiated with light, and contains a known binder resin, plasticizer, sensitizer and the like as necessary. As the charge generation material, those commonly used in this field can be used. For example, perylene pigments such as perylene imide and perylene anhydride, polycyclic quinone pigments such as quinacridone and anthraquinone, phthalocyanine pigments such as metal and metal-free phthalocyanine, halogenated metal-free phthalocyanine, squalium dye, azurenium dye, thiapyrylium Examples include azo pigments having a dye, a carbazole skeleton, a styryl stilbene skeleton, a triphenylamine skeleton, a dibenzothiophene skeleton, an oxadiazole skeleton, a fluorenone skeleton, a bis stilbene skeleton, a distyryl oxadiazole skeleton, or a distyryl carbazole skeleton. it can.

  Among these, metal-free phthalocyanine pigments, oxotitanyl phthalocyanine pigments, bisazo pigments containing a fluorene ring and / or a fluorenone ring, bisazo pigments composed of aromatic amines, trisazo pigments, etc. have high charge generation ability and high sensitivity. Suitable for obtaining a photosensitive layer. The charge generation materials may be used alone or in combination of two or more. The content of the charge generation material is not particularly limited, but is preferably 5 parts by weight or more and 500 parts by weight or less with respect to 100 parts by weight of the binder resin in the charge generation layer. More preferably, it is 200 parts by weight or less. The binder resin for the charge generation layer is not particularly limited, and those commonly used in this field can be used. Examples include melamine resin, epoxy resin, silicon resin, polyurethane, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polycarbonate, phenoxy resin, polyvinyl butyral, polyarylate, polyamide, polyester, and the like. Binder resin may be used individually by 1 type, or may use 2 or more types together as needed.

  The charge generation layer generates charge by dissolving or dispersing an appropriate amount of a charge generation material, a binder resin, and, if necessary, a plasticizer and a sensitizer in an appropriate organic solvent capable of dissolving or dispersing these components. It can be formed by preparing a layer coating solution, applying the charge generation layer coating solution to the surface of the conductive substrate, and drying. The film thickness of the charge generation layer thus obtained is not particularly limited, but is preferably 0.05 μm or more and 5 μm or less, more preferably 0.1 μm or more and 2.5 μm or less. .

  The charge transport layer laminated on the charge generation layer has a charge transport material having the ability to accept and transport charges generated from the charge generation material and a binder resin for the charge transport layer as essential components, and if necessary You may contain a well-known antioxidant, a plasticizer, a sensitizer, a lubricant, etc. As the charge transport material, those commonly used in this field can be used. For example, poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensate and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, oxadiazole derivatives, imidazole derivatives 9- (p-diethylaminostyryl) anthracene, 1,1-bis (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, pyrazoline derivatives, phenylhydrazones, hydrazone derivatives, triphenylamine compounds, tetra Electron-donating substances such as phenyldiamine compounds, triphenylmethane compounds, stilbene compounds, azine compounds having a 3-methyl-2-benzothiazoline ring, fluorenone derivatives, dibens Thiophene derivatives, indenothiophene derivatives, phenanthrenequinone derivatives, indenopyridine derivatives, thioxanthone derivatives, benzo [c] cinnoline derivatives, phenazine oxide derivatives, tetracyanoethylene, tetracyanoquinodimethane, promanyl, chloranil, benzoquinone, etc. An electron accepting substance can be mentioned.

  A charge transport material may be used individually by 1 type, or may use 2 or more types together. The content of the charge transport material is not particularly limited, but is preferably 10 parts by weight or more and 300 parts by weight or less with respect to 100 parts by weight of the binder resin in the charge transport material, and 30 parts by weight or more. It is preferably 150 parts by weight or less. The binder resin for the charge transport layer is not particularly limited, and a resin commonly used in this field and capable of uniformly dispersing the charge transport material can be used. Examples thereof include polycarbonate, polyarylate, polyvinyl butyral, polyamide, polyester, polyketone, epoxy resin, polyurethane, polyvinyl ketone, polystyrene, polyacrylamide, phenol resin, phenoxy resin, polysulfone resin, and copolymer resins thereof. Among these, in consideration of film formability, wear resistance of the resulting charge transport layer, electrical characteristics, etc., polycarbonate containing bisphenol Z as a monomer component (hereinafter referred to as “bisphenol Z type polycarbonate”), bisphenol Z type polycarbonate And a mixture of polycarbonate with other polycarbonates are preferred. The said binder resin may be used individually by 1 type, or may use 2 or more types together.

  The charge transport layer preferably contains an antioxidant together with the charge transport material and the binder resin for the charge transport layer. As the antioxidant, those commonly used in this field can be used. For example, vitamin E, hydroquinone, hindered amine, hindered phenol, paraphenylenediamine, arylalkane and derivatives thereof, organic sulfur compounds, organic phosphorus compounds, and the like can be given. The said antioxidant may be used individually by 1 type, or may use 2 or more types together. The content of the antioxidant is not particularly limited, but is 0.01% by weight to 10% by weight, preferably 0.05% by weight to 5% by weight of the total amount of the components constituting the charge transport layer. % To be added.

  The charge transport layer is prepared by dissolving an appropriate amount of a charge transport material and a binder resin, and, if necessary, an antioxidant, a plasticizer, a sensitizer and the like in an appropriate organic solvent capable of dissolving or dispersing these components. It can be formed by dispersing to prepare a charge transport layer coating solution, applying the charge transport layer coating solution to the surface of the charge generation layer, and drying.

  The thickness of the charge generation layer thus obtained is not particularly limited, but is preferably 10 μm or more and 50 μm or less, and more preferably 15 μm or more and 40 μm or less. Note that a photosensitive layer in which a charge generation material and a charge transport material are present can be formed in one layer. In that case, the type, content, type of binder resin, and other additives of the charge generation material and the charge transport material are the same as in the case of separately forming the charge generation layer and the charge transport layer. be able to.

  In this embodiment, the photosensitive drum formed by forming the organic photosensitive layer using the charge generation material and the charge transport material as described above is used, but the photosensitive drum formed by forming the inorganic photosensitive layer using silicon or the like. Can be used instead.

Charging unit The charging unit 12 faces the photoconductive drum 11 and is arranged so as to be separated from the surface of the photoconductive drum 11 along the longitudinal direction of the photoconductive drum 11 with a gap. Charge to polarity and potential. The charging unit 12 may be a charging brush type charger, a charger type charger, a sawtooth type charger, an ion generator, or the like. In the present embodiment, the charging unit 12 is provided so as to be separated from the surface of the photosensitive drum 11, but is not limited thereto. For example, a charging roller may be used as the charging unit 12 and the charging roller may be disposed so that the charging roller and the photosensitive drum 11 are in pressure contact with each other, or a contact charging type charger such as a charging brush or a magnetic brush may be used. Good.

Exposure Unit The exposure unit 13 is arranged so that light of each color information emitted from the exposure unit 13 passes between the charging unit 12 and the developing device 14 and is irradiated on the surface of the photosensitive drum 11. The exposure unit 13 branches the image information into light of each color information of b, c, m, and y in the unit, and the surface of the photosensitive drum 11 charged to a uniform potential by the charging unit 12 is light of each color information. To form an electrostatic latent image on the surface. As the exposure unit 13, for example, a laser scanning unit including a laser irradiation unit and a plurality of reflection mirrors can be used. In addition, a unit in which an LED (Light Emitting Diode) array, a liquid crystal shutter, and a light source are appropriately combined may be used.

Developing Device The configuration of the developing device 14 will be described with reference to the cross-sectional view shown in FIG. The developing device 14 performs development using a one-component developer or a two-component developer containing the capsule toner according to the present invention. That is, since the developing device 14 performs development using the developer containing the toner that can maintain sufficient fixability for a long period of time, a toner image can be formed on the photosensitive drum 11.

  The developing device 14 includes a developing tank 20 and a toner hopper 21. The developing tank 20 is disposed so as to face the surface of the photosensitive drum 11, and is a container that supplies toner to the electrostatic latent image formed on the surface of the photosensitive drum 11 and develops it to form a visible toner image. It is a shaped member. The developing tank 20 contains a one-component developer or a two-component developer containing the capsule toner according to the present invention in its internal space, and is a roller member such as the developing roller 22, the supply roller 23, the stirring roller 24, or a screw member. And supports them rotatably. An opening is formed in a side surface of the developing tank 20 facing the photosensitive drum 11, and a developing roller 22 is provided at a position facing the photosensitive drum 11 through the opening.

  The developing roller 22 is a roller-like member that supplies the capsule toner according to the present invention to the electrostatic latent image on the surface of the photosensitive drum 11 at the pressure contact portion or the closest portion to the photosensitive drum 11. When supplying the toner, a potential having a polarity opposite to the charging potential of the toner is applied to the surface of the developing roller 22 as a developing bias voltage (hereinafter simply referred to as “developing bias”). As a result, the toner on the surface of the developing roller 22 is smoothly supplied to the electrostatic latent image. Further, by changing the developing bias value, the amount of toner (toner adhesion amount) supplied to the electrostatic latent image can be controlled.

  The supply roller 23 is a roller-like member that faces the developing roller 22 and can be rotationally driven, and supplies the one-component developer or the two-component developer containing the capsule toner according to the present invention to the periphery of the developing roller 22. The agitation roller 24 is a roller-like member that faces the supply roller 23 and can be driven to rotate, and feeds the capsule toner according to the present invention newly supplied from the toner hopper 21 into the developing tank 20 to the periphery of the supply roller 23. . The toner hopper 21 is provided so that a toner replenishing port (not shown) provided at the lower part in the vertical direction communicates with a toner receiving port (not shown) provided at the upper part in the vertical direction of the developing tank 20. The toner is replenished according to the toner consumption status of 20. Further, the toner may be directly supplied from each color toner cartridge without using the toner hopper 21.

Cleaning Unit The cleaning unit 15 shown in FIG. 3 cleans the surface of the photosensitive drum 11 by removing the toner remaining on the surface of the photosensitive drum 11 after transferring the toner image to the recording medium. For the cleaning unit 15, for example, a plate-like member such as a cleaning blade is used. In the image forming apparatus 100, an organic photosensitive drum is mainly used as the photosensitive drum 11, and the surface of the organic photosensitive drum is mainly composed of a resin component. Therefore, the image forming apparatus 100 is generated by corona discharge by a charging device. Surface degradation is likely to proceed due to the chemical action of ozone. However, the deteriorated surface portion is worn by receiving a rubbing action by the cleaning unit 15 and is gradually but surely removed. Therefore, the problem of surface deterioration due to ozone or the like is practically solved, and the charging potential by the charging operation can be stably maintained over a long period of time. Although the cleaning unit 15 is provided in the present embodiment, it is not particularly limited, and the cleaning unit 15 may not be provided.

  According to the toner image forming unit 7, the surface of the photosensitive drum 11 that is uniformly charged by the charging unit 12 is irradiated with signal light corresponding to image information from the exposure unit 13 to form an electrostatic latent image, Toner is supplied from the developing device 14 to form a toner image. After the toner image is transferred to the intermediate transfer belt 25, the toner remaining on the surface of the photosensitive drum 11 is removed by the cleaning unit 15. This series of toner image forming operations is repeatedly executed.

(Transfer part)
The transfer unit 8 is disposed above the photosensitive drum 11, and includes an intermediate transfer belt 25, a driving roller 26, a driven roller 27, an intermediate transfer roller 28 (b, c, m, y), and a transfer belt cleaning unit. 29 and the transfer roller 30. The intermediate transfer belt 25 is an endless belt member that is stretched by a driving roller 26 and a driven roller 27 to form a loop-shaped movement path, and is driven to rotate in the direction of arrow B. When the intermediate transfer belt 25 passes through the photosensitive drum 11 while being in contact with the photosensitive drum 11, an intermediate transfer roller 28 disposed on the surface of the photosensitive drum 11 is opposed to the photosensitive drum 11 via the intermediate transfer belt 25. A transfer bias having a polarity opposite to the charging polarity of the toner is applied, and the toner image formed on the surface of the photosensitive drum 11 is transferred onto the intermediate transfer belt 25.

  In the case of a full-color image, each color toner image formed on each photoconductor drum 11 is sequentially transferred onto the intermediate transfer belt 25 to form a full-color toner image. The drive roller 26 is provided so as to be rotatable around its axis by a drive unit (not shown), and the intermediate transfer belt 25 is rotated in the direction of arrow B by the rotation drive. The driven roller 27 is provided so as to be able to rotate following the rotational driving of the driving roller 26, and applies a constant tension to the intermediate transfer belt 25 so that the intermediate transfer belt 25 does not loosen. The intermediate transfer roller 28 is provided so as to be in pressure contact with the photosensitive drum 11 via the intermediate transfer belt 25 and to be rotatable around its axis by a drive unit (not shown). The intermediate transfer roller 28 is connected to a power source (not shown) for applying a transfer bias as described above, and has a function of transferring the toner image on the surface of the photosensitive drum 11 to the intermediate transfer belt 25.

  The transfer belt cleaning unit 29 is provided so as to face the driven roller 27 through the intermediate transfer belt 25 and to contact the outer peripheral surface of the intermediate transfer belt 25. Since the toner adhering to the intermediate transfer belt 25 due to contact with the photosensitive drum 11 causes the back surface of the recording medium to be contaminated, the transfer belt cleaning unit 29 removes and collects the toner on the surface of the intermediate transfer belt 25. The transfer roller 30 is provided so as to be in pressure contact with the drive roller 26 via the intermediate transfer belt 25 and to be rotatable around an axis by a drive unit (not shown). At the pressure contact portion (transfer nip portion) between the transfer roller 30 and the drive roller 26, the toner image carried and conveyed by the intermediate transfer belt 25 is transferred to a recording medium fed from the recording medium supply unit 5 described later. Is done. The recording medium carrying the toner image is fed to the fixing device 4. According to the transfer unit 8, the toner image transferred from the photosensitive drum 11 to the intermediate transfer belt 25 at the pressure contact portion between the photosensitive drum 11 and the intermediate transfer roller 28 is driven to rotate in the direction of arrow B of the intermediate transfer belt 25. Is transferred to the transfer nip portion, where it is transferred to a recording medium.

(Fixing device)
In the image forming apparatus of the present invention, the fixing device is a fixing device using the above-described fixing method according to the present invention.
The fixing device 4 includes a laser fixing device 80 provided downstream of the transfer unit 8 in the conveyance direction of the recording medium.
The fixing device 4 is as described above in <Fixing method and device>.

(Recording medium supply unit)
The recording medium supply unit 5 shown in FIG. 3 includes an automatic paper feed tray 35, a pickup roller 36, a transport roller 37, a registration roller 38, and a manual paper feed tray 39. The automatic paper feed tray 35 is a container-like member that is provided in the lower part of the image forming apparatus 100 in the vertical direction and stores a recording medium. Examples of the recording medium include plain paper, color copy paper, overhead projector sheet, and postcard. The pick-up roller 36 takes out the recording medium stored in the automatic paper feed tray 35 one by one and feeds it to the paper transport path S1. The conveyance rollers 37 are a pair of roller members provided so as to be in pressure contact with each other, and convey the recording medium toward the registration rollers 38.

  The registration rollers 38 are a pair of roller members provided so as to be in pressure contact with each other, and the recording medium fed from the conveyance roller 37 is used to convey the toner image carried on the intermediate transfer belt 25 to the transfer nip portion. Synchronously, it is fed to the transfer nip. The manual paper feed tray 39 is a device for taking a recording medium into the image forming apparatus 100 by a manual operation. The recording medium taken from the manual paper feed tray 39 passes through the paper conveyance path S2 by the conveyance roller 37. Then, it is fed to the registration roller 38. According to the recording medium supply unit 5, the toner image carried on the intermediate transfer belt 25 is conveyed to the transfer nip portion of the recording medium supplied one by one from the automatic paper feed tray 35 or the manual paper feed tray 39. In synchronism with this, the sheet is fed to the transfer nip portion.

(Discharge part)
The discharge unit 6 includes a conveyance roller 37, a discharge roller 40, and a discharge tray 41. The conveyance roller 37 is provided downstream of the fixing nip portion in the sheet conveyance direction, and conveys the recording medium on which the image is fixed by the fixing device 4 toward the discharge roller 40. The discharge roller 40 discharges the recording medium on which the image is fixed to a discharge tray 41 provided on the upper surface in the vertical direction of the image forming apparatus 100. The discharge tray 41 stores a recording medium on which an image is fixed.

  The image forming apparatus 100 includes a control unit (not shown). For example, the control unit is provided in an upper part of the internal space of the image forming apparatus 100 and includes a storage unit, a calculation unit, and a control unit. In the storage unit of the control means, various setting values via an operation panel (not shown) arranged on the upper surface of the image forming apparatus 100, detection results from sensors (not shown) arranged at various locations inside the image forming apparatus 100, external devices The image information from is input. In addition, programs for executing various means are written. Examples of the various means include a recording medium determination unit that determines a recording medium, an adhesion amount control unit that controls the toner adhesion amount, and a fixing condition control unit that controls toner fixing conditions. As the storage unit, those commonly used in this field can be used, and examples thereof include a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD).

  As the external device, an electric / electronic device that can form or acquire image information and can be electrically connected to the image forming apparatus 100 can be used. For example, a computer, a digital camera, a television receiver, a video recorder, a DVD (Digital Versatile Disc) recorder, an HDDVD (High-Definition Digital Versatile Disc), a Blu-ray disc recorder, a facsimile device, a portable terminal device, and the like can be given. The calculation unit retrieves various data (image formation command, detection result, image information, etc.) written in the storage unit and programs of various means, and performs various determinations. The control unit sends a control signal to the corresponding device according to the determination result of the calculation unit, and performs operation control. The control unit and the calculation unit include a processing circuit realized by a microcomputer, a microprocessor, or the like provided with a central processing unit (CPU). The control means includes a main power supply together with the processing circuit described above, and the power supply supplies power not only to the control means but also to each device in the image forming apparatus 100.

As mentioned above, although embodiment of this invention was described in detail, this invention is not limited to this.
In the present specification, “A to B” indicating a range means “A or more and B or less”.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by an Example.
<Volume average particle diameter>
20 ml of a sample and 1 ml of sodium alkyl ether sulfate are added to 50 ml of an electrolytic solution (trade name: ISOTON-II, manufactured by Beckman Coulter Co., Ltd.), and ultrasonic dispersion (trade name: UH-50, manufactured by SMT Corporation) is added. The sample for measurement was prepared by dispersing for 3 minutes at an ultrasonic frequency of 20 kHz. About this measurement sample, using a particle size distribution measuring device (trade name: Multisizer III, manufactured by Beckman Coulter Co., Ltd.), measurement is performed under the conditions of an aperture diameter of 100 μm and the number of measured particles of 50000 counts. The volume average particle size was determined.

<Glass transition temperature (Tg) of binder resin>
Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), according to Japanese Industrial Standard (JIS) K7121-1987, 1 g of a sample is heated at a heating rate of 10 ° C. per minute and a DSC curve is measured. did. Draw the endothermic peak corresponding to the glass transition of the obtained DSC curve at a point where the slope is maximum with respect to the straight line that extends the base line on the high temperature side to the low temperature side and the curve from the rising part of the peak to the vertex. The temperature at the intersection with the tangent line was determined as the glass transition temperature (Tg).

<Softening temperature of binder resin (Tm)>
In a flow characteristic evaluation apparatus (trade name: Flow Tester CFT-100C, manufactured by Shimadzu Corporation), a load of 10 kgf / cm ² (9.8 × 10 ⁵ Pa) was applied and a sample 1 g was a die (nozzle diameter 1 mm, length). 1 mm) was set to be extruded, heated at a heating rate of 6 ° C. per minute, and the temperature at which half of the sample flowed out from the die was determined as the softening temperature.

1. Manufacture of two-component developer
(Example 1)
(1) Production of core particles 87.5 parts of styrene acrylic resin as binder resin, glass transition temperature Tg: 55 ° C., softening temperature Tm: 110 ° C., and colorant (CI Pigment Blue 15; pigment particles) 8 parts of 0.75 μm in diameter) and 1.5 parts of charge control agent (product: Bontron E84, manufactured by Orient Chemical Co., Ltd.) are mixed in a mixer (trade name: Henschel mixer, manufactured by Mitsui Mining Co., Ltd.). did. Using a twin-screw extruder (trade name: PCM-30, manufactured by Ikegai Co., Ltd.), the obtained mixture was melt-kneaded under conditions of a cylinder temperature of 145 ° C. and a barrel rotation speed of 300 rpm to prepare a melt-kneaded product. . The melt-kneaded product was cooled to room temperature and then coarsely pulverized with a cutter mill (trade name: VM-16, manufactured by Seishin Enterprise Co., Ltd.) to prepare a coarse powder having a particle size of 100 μm or less.

  40 g of the obtained coarse powder, 13.3 g of xanthan gum, sodium dodecylbenzenesulfonate (trade name: LUNOX S-100, anionic dispersant, manufactured by Toho Chemical Co., Ltd.), sulfosuccinic acid surfactant (trade name: Air roll CT-1p, main component: dioctyl sulfosuccinate sodium salt, manufactured by Toho Chemical Co., Ltd.) 0.67 g, and the balance as water, the coarse powder slurry raw materials were mixed to a total of 800 g, and the resulting mixture The mixture was introduced into a mixer (trade name: New Generation Mixer NGM-1.5TL, manufactured by Mie Co., Ltd.), stirred at 2000 rpm for 5 minutes, and then deaerated to obtain a coarse powder slurry.

  800 g of the obtained coarse powder slurry was put into a tank of a high-pressure homogenizer (trade name: NANO3000, manufactured by Miki Co., Ltd.) and maintained at a temperature of 185 ° C. and under a pressurized condition of 210 MPa, Was circulated for 30 minutes to obtain a slurry of resin particles.

  600 g of the obtained resin particle slurry and 30 g of a 20% aqueous solution of stearyltrimethylammonium chloride (trade name: Cotamine 86W, manufactured by Kao Corporation) are granulated (product name: New Generation Mixer NGM-1.5TL, stock) The product was stirred at 75 ° C. and 2000 rpm for 30 minutes, then heated to 85 ° C. and further stirred for 2 hours. In order to agglomerate unagglomerated fine powder, 300 g of water was added after the temperature was raised and rapidly cooled to room temperature to obtain a core particle slurry. The volume average particle diameter of the obtained core particles was 7 μm.

(2) Shell particles Shell particles for shell layer formation are melted in the same manner and with the same materials and blending amounts as those used for the production of core particles, except that the colorant is changed to one having a volume average particle size of 0.2 μm. After kneading, a dispersion of shell particles having a volume average particle size of 0.1 μm was obtained with a high-pressure homogenizer.

(3) Production of Capsule Toner 450 g of the core particle slurry and 45 g of the shell layer particle slurry obtained as described above were mixed into a 500 ml rotor / screen type high-speed emulsifier (CLEAMIX, M. Transferred to Technic Co., Ltd.), the rotational speed of the rotating body part was set to 18 m / second, treated at a liquid temperature of 80 ° C. for 10 minutes, then filtered to remove the particles, washed with water 5 times, Was dried with hot air at 75 ° C. to obtain a capsule toner.

(4) Production of two-component developer 100 parts by weight of the obtained capsule toner, 2.2 parts by weight of hydrophobic silica (trade name: R-974, manufactured by Nippon Aerosil Co., Ltd.) as an external additive, and hydrophobic titanium (Product name: T-805, manufactured by Nippon Aerosil Co., Ltd.) and 1.6 parts by weight are mixed with a Henschel mixer (trade name: FM mixer, manufactured by Mitsui Mining Co., Ltd.) to add an external additive to the toner. did.
A ferrite core carrier having a volume average particle diameter of 45 μm is used as the carrier, and a V-type mixer / mixer (trade name: V-5, manufactured by Tokuju Kogyo Co., Ltd.) so that the toner concentration in the developer is 7%. Was mixed for 20 minutes to prepare a two-component developer of Example 1.

(Examples 2 to 5 and Comparative Examples 1 to 4)
Examples 2 to 5 were carried out in the same manner as Example 1 except that the volume average particle diameter of the colorant fine particles used in the core particles and / or the colorant fine particles used in the shell particles was changed as shown in Table 1. And the two-component developer of Comparative Examples 1-4 was produced.

2. Evaluation of Fixability The fixing device of a commercially available copying machine (trade name: MX-2700, manufactured by Sharp Corporation) is a fixing device (Y fixing laser: 430 nm, M fixing laser: 565 nm, C fixing laser) as shown in FIG. : 620 nm, K fixing laser: 780 nm, output: output: 250 W / cm ² ), the two-component developers of Examples and Comparative Examples were respectively filled. The solid image was fixed by adjusting the toner adhesion amount to 1.2 mg / cm ² (corresponding to two capsule toner layers), and an evaluation image was prepared.

  Using the sand eraser (trade name: Lion Eraser Gaza Sand, manufactured by Lion Koki Co., Ltd.) with a load of 1 kg on the surface of the evaluation image created, the speed of 14 mm / s And rubbed for 3 round trips. The optical reflection density (image density) before and after rubbing was measured using a reflection densitometer (trade name: RD-914, manufactured by Macbeth), and the fixing rate was calculated.

The fixing rate was determined using the following formula (1).
Fixing rate (%) = [(Image density after rubbing) / (Image density before rubbing)] × 100 (1)
When the fixing ratio obtained by the above formula (1) was 70% or more, it was evaluated as a capsule toner having sufficient fixing ability.

Table 1 shows the fixing ratios of the two-component developers of Examples 1 to 5 and Comparative Examples 1 to 4.
As a result of evaluating the fixability, it has been revealed that the developer containing the capsule toner of the present invention can ensure a sufficient fixability only by the laser fixing system.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The capsule toner of the present invention can be applied to a one-component developer containing the toner and an external additive, or a two-component developer containing the toner and a carrier, and an image forming apparatus provided with a laser fixing system as a fixing device. Applicable to the device.

1 Capsule toner 2 Core particles 3 Shell layer (coating layer)
C1 Colorant fine particles in core particle C2 Colorant fine particles in shell layer a Volume average particle size of colorant fine particles in core particle b Volume average particle size of colorant fine particles in coat layer

4 Fixing Device 7 Toner Image Forming Unit 11 Photosensitive Drum 12 Charging Unit 13 Exposure Unit 14 Developing Device 15 Cleaning Unit

DESCRIPTION OF SYMBOLS 20 Developing tank 21 Toner hopper 22 Developing roller 23 Supply roller 24 Stirring roller 25 Intermediate transfer belt 26 Intermediate transfer belt drive roller 27 Intermediate transfer belt driven roller 28 Intermediate transfer roller

29 Transfer Belt Cleaning Unit 30 Transfer Roller 35 Automatic Paper Feed Tray 36 Pickup Roller 37 Transport Roller 38 Registration Roller 39 Manual Feed Tray 40 Ejection Roller 41 Ejection Tray

61 Endless Belt 62 Drive Roller 63 Driven Roller 80 Laser Fixing Device 81 Laser Light Source 82 Rotating Polyhedral Mirror

100 Image forming apparatus P Paper (recording medium)
S1 Paper transport path S2 Paper transport path

Claims (7)

  Volume average particles of colorant fine particles in the core particles, comprising at least core particles composed of binder resin and colorant fine particles, and at least a binder resin and colorant fine particles and a coating layer covering the core particles. The diameter a and the volume average particle diameter b of the colorant fine particles in the coating layer satisfy the following relationship: 2.0 ≦ a / b ≦ 5.0 and 0.5 μm ≦ a ≦ 0.9 μm. An electrophotographic capsule toner having a core-shell structure, which is irradiated only with light.   The toner according to claim 1, further satisfying the following relationship: 0.1 μm ≦ b ≦ 0.4 μm.   The toner according to claim 1, wherein the toner is a cyan toner, a magenta toner, or a yellow toner.   An electrophotographic one-component developer comprising the toner according to any one of claims 1 to 3 and an external additive.   An electrophotographic two-component developer comprising the toner according to any one of claims 1 to 3 and a carrier.   An unfixed toner image formed with the toner according to any one of claims 1 to 3 is irradiated on the recording medium with a laser beam having a wavelength within the absorption wavelength range of the colorant fine particles contained in the toner. A toner image fixing method, wherein the toner image is melted and then solidified again to fix the toner image on the recording medium. A fixing device using at least one developer according to claim 4 or 5 and fixing an unfixed toner image formed with the toner in the developer onto a recording medium, wherein the toner is Means for heating and melting, each means comprising at least one laser light source for irradiating each of the toners with laser light having a wavelength within the absorption wavelength range of the colorant fine particles contained in each toner; and An electrophotographic image forming apparatus , comprising: a fixing device including only the laser light source as a light source for irradiating light to the light source .

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